Downgrade unnested_or_patterns to pedantic
Even with #5704 fixed, I don't believe it is a safe bet that if someone is using or-patterns anywhere in a codebase then they want to use it as much as possible in the whole codebase. I think it would be reasonable to reevaluate after the feature is stable. I feel that a warn-by-default lint suggesting use of an unstable feature, even if already being used in one place, is questionable.
changelog: Remove unnested_or_patterns from default set of enabled lints
1f39eeb06d